TOPIC: COMMAND SUBSTITUTION
File comparison using PowerShell
16th August 2025In the past, I have compared files on the Linux/UNIX command line as well as the legacy Windows command line. Recently, I decided to try it using PowerShell. Here is the command structure:
Compare-Object (Get-Content ".\[name of one text file]") (Get-Content ".\[name of another text file]") > [path and name of output file]
Admittedly, this is more verbose than the others that I have mentioned above. Nevertheless, it does the job and sends everything to a text file for review. The Compare-Object piece does the comparison once the Get-Content portions have read in the content.
Smarter file renaming using PowerShell
14th November 2014It appears that the Rename-Item commandlet in PowerShell is a very useful tool when it comes to smarter renaming of files. Even text substitution is a possibility, and what follows is an example that takes the output of the Dir command for listing the files in a directory and replaces hyphens with underscores in each one.
Dir | Rename-Item –NewName { $_.name –replace “-“,”_” }
The result is that something like the-file.txt becomes the_file.txt. This behaviour is reminiscent of the rename command found on Linux and UNIX systems, where regular expressions can be used, like in the following example that has the same result as the above:
rename 's/-/_/g' *
In both cases, you do need to be careful as to what files are in a directory for this, though the wildcard syntax on Linux or UNIX will be more familiar to anyone who has worked with files via almost any command line. Another thing to watch in the UNIX world is that * parses the whole directory structure, and that could be something that is not wanted for much of the time.
All of this is a far cry from the capabilities of the ren or rename command used in the days of MS-DOS and what has become the legacy Windows command line. Apart from simple renaming, any attempt at tweaking a filename through substitution ended up with the extra string getting appended to filenames when I tried it. Thus, the PowerShell option looks better in comparison.